// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE

// Highlighting text that matches the selection
//
// Defines an option highlightSelectionMatches, which, when enabled,
// will style strings that match the selection throughout the
// document.
//
// The option can be set to true to simply enable it, or to a
// {minChars, style, wordsOnly, showToken, delay} object to explicitly
// configure it. minChars is the minimum amount of characters that should be
// selected for the behavior to occur, and style is the token style to
// apply to the matches. This will be prefixed by "cm-" to create an
// actual CSS class name. If wordsOnly is enabled, the matches will be
// highlighted only if the selected text is a word. showToken, when enabled,
// will cause the current token to be highlighted when nothing is selected.
// delay is used to specify how much time to wait, in milliseconds, before
// highlighting the matches. If annotateScrollbar is enabled, the occurences
// will be highlighted on the scrollbar via the matchesonscrollbar addon.

(function(mod) {
  if (typeof exports == 'object' && typeof module == 'object')
    // CommonJS
    mod(require('../../lib/codemirror'), require('./matchesonscrollbar'));
  else if (typeof define == 'function' && define.amd)
    // AMD
    define(['../../lib/codemirror', './matchesonscrollbar'], mod);
  // Plain browser env
  else mod(CodeMirror);
})(function(CodeMirror) {
  'use strict';

  var defaults = {
    style: 'matchhighlight',
    minChars: 2,
    delay: 100,
    wordsOnly: false,
    annotateScrollbar: false,
    showToken: false,
    trim: true,
  };

  function State(options) {
    this.options = {};
    for (var name in defaults)
      this.options[name] = (options && options.hasOwnProperty(name)
        ? options
        : defaults)[name];
    this.overlay = this.timeout = null;
    this.matchesonscroll = null;
    this.active = false;
  }

  CodeMirror.defineOption('highlightSelectionMatches', false, function(
    cm,
    val,
    old,
  ) {
    if (old && old != CodeMirror.Init) {
      removeOverlay(cm);
      clearTimeout(cm.state.matchHighlighter.timeout);
      cm.state.matchHighlighter = null;
      cm.off('cursorActivity', cursorActivity);
      cm.off('focus', onFocus);
    }
    if (val) {
      var state = (cm.state.matchHighlighter = new State(val));
      if (cm.hasFocus()) {
        state.active = true;
        highlightMatches(cm);
      } else {
        cm.on('focus', onFocus);
      }
      cm.on('cursorActivity', cursorActivity);
    }
  });

  function cursorActivity(cm) {
    var state = cm.state.matchHighlighter;
    if (state.active || cm.hasFocus()) scheduleHighlight(cm, state);
  }

  function onFocus(cm) {
    var state = cm.state.matchHighlighter;
    if (!state.active) {
      state.active = true;
      scheduleHighlight(cm, state);
    }
  }

  function scheduleHighlight(cm, state) {
    clearTimeout(state.timeout);
    state.timeout = setTimeout(function() {
      highlightMatches(cm);
    }, state.options.delay);
  }

  function addOverlay(cm, query, hasBoundary, style) {
    var state = cm.state.matchHighlighter;
    cm.addOverlay((state.overlay = makeOverlay(query, hasBoundary, style)));
    if (state.options.annotateScrollbar && cm.showMatchesOnScrollbar) {
      var searchFor = hasBoundary ? new RegExp('\\b' + query + '\\b') : query;
      state.matchesonscroll = cm.showMatchesOnScrollbar(searchFor, false, {
        className: 'CodeMirror-selection-highlight-scrollbar',
      });
    }
  }

  function removeOverlay(cm) {
    var state = cm.state.matchHighlighter;
    if (state.overlay) {
      cm.removeOverlay(state.overlay);
      state.overlay = null;
      if (state.matchesonscroll) {
        state.matchesonscroll.clear();
        state.matchesonscroll = null;
      }
    }
  }

  function highlightMatches(cm) {
    cm.operation(function() {
      var state = cm.state.matchHighlighter;
      removeOverlay(cm);
      if (!cm.somethingSelected() && state.options.showToken) {
        var re =
          state.options.showToken === true ? /[\w$]/ : state.options.showToken;
        var cur = cm.getCursor(),
          line = cm.getLine(cur.line),
          start = cur.ch,
          end = start;
        while (start && re.test(line.charAt(start - 1))) --start;
        while (end < line.length && re.test(line.charAt(end))) ++end;
        if (start < end)
          addOverlay(cm, line.slice(start, end), re, state.options.style);
        return;
      }
      var from = cm.getCursor('from'),
        to = cm.getCursor('to');
      if (from.line != to.line) return;
      if (state.options.wordsOnly && !isWord(cm, from, to)) return;
      var selection = cm.getRange(from, to);
      if (state.options.trim) selection = selection.replace(/^\s+|\s+$/g, '');
      if (selection.length >= state.options.minChars)
        addOverlay(cm, selection, false, state.options.style);
    });
  }

  function isWord(cm, from, to) {
    var str = cm.getRange(from, to);
    if (str.match(/^\w+$/) !== null) {
      if (from.ch > 0) {
        var pos = { line: from.line, ch: from.ch - 1 };
        var chr = cm.getRange(pos, from);
        if (chr.match(/\W/) === null) return false;
      }
      if (to.ch < cm.getLine(from.line).length) {
        var pos = { line: to.line, ch: to.ch + 1 };
        var chr = cm.getRange(to, pos);
        if (chr.match(/\W/) === null) return false;
      }
      return true;
    } else return false;
  }

  function boundariesAround(stream, re) {
    return (
      (!stream.start || !re.test(stream.string.charAt(stream.start - 1))) &&
      (stream.pos == stream.string.length ||
        !re.test(stream.string.charAt(stream.pos)))
    );
  }

  function makeOverlay(query, hasBoundary, style) {
    return {
      token: function(stream) {
        if (
          stream.match(query) &&
          (!hasBoundary || boundariesAround(stream, hasBoundary))
        )
          return style;
        stream.next();
        stream.skipTo(query.charAt(0)) || stream.skipToEnd();
      },
    };
  }
});
